Conventionally, a color scanner may include a unit configured to photoelectrically scan an image and convert the image into digital information. Such a unit may be referred to as a “reading unit.” A reading unit may include an illumination system, e.g., fluorescent white light, incandescent lamp source, Light Emitting Diodes (LEDs), that produces light which is reflected from the document to be scanned. The light reflected from the document is directed through a focusing device to filter out the primary colors into particular linear Charge Coupled Device (CCD) arrays, e.g., a red CCD array, a green CCD array, and a blue CCD array. Hence, the reflected image of the document may be separated into the primary colors which are directed onto separate CCD arrays. A color scanner may further include an apparatus configured to move the location where the reading unit is measuring so as to digitize an entire two dimensional area.
The CCD arrays may be configured to read the reflected light from the same portion of the document either at different times or simultaneously. In either case, the red color CCD array is activated to read a line scan image in a plane, referred to as a “red color plane.” Further, the green color CCD array is activated to read a line scan image in a plane, referred to as the “green color plane” and the blue color CCD array is activated to read a line scan image in a plane, referred to as the “blue color plane.” If these color planes are not aligned, a phenomenon, commonly referred to as “color misregistration,” may occur.
Color misregistration may cause black or color text, or in the case of an image or graphic having edges, cause it to become blurred with color outlines. This is especially problematic when making copies of such text, graphics or images with blurred color outlines, as the copying process adds additional color misregistration from the printer. Further, if color misregistration is different in the horizontal and vertical directions when the text is converted to black, then the relative thickness of text strokes may also be different horizontally and vertically thereby causing the text to appear unbalanced.
Currently, the methods for detecting and correcting color misregistration involve complex computations using significant processing power.
Therefore, there is a need in the art to detect and calculate the amount of color misregistration using a simple algorithm that may be used to calibrate the color scanner to compensate for the detected color misregistration.